Traditionally, editors of documents, such as web pages, manually selected portions of the documents to augment with additional information. For example, an editor might choose to associate various terms in the document with assorted hyperlinks to other documents. Unfortunately, there are a number of problems with this approach. For example, it can be difficult to determine which terms to highlight and it can also be difficult to determine which destinations should be selected for respective hyperlinks. Another problem is that for certain documents, it is not possible and/or not typical to augment content, even though doing so may benefit readers. As one example, messages posted to message boards typically include relatively few hyperlinks to other content. An additional problem is that the passage of time can potentially render both the selected portions of the document and the corresponding additional information out of date. Attempts to automatically augment document content are also problematic. For example, a publisher might choose to automatically link any occurrences in a document of phrases, such as “diet drug,” to advertising sites. Readers, encountering such links, may erroneously believe that they have been inserted manually and meant to enhance their knowledge of key aspects of the document. When they follow the links, they may become annoyed and/or feel as if they have been tricked into following a link, potentially resulting in a loss of goodwill toward both the publisher and the advertiser.